1. Field of the Invention
This invention relates generally to bicycle brake lever assemblies and more particularly to a brake assembly having a partially slotted brake lever housing.
2. Related Art
Bicycle brake systems comprise an actuating assembly or brake lever, operatively connected by a control cable within a housing (i.e. Bowden cable) to a responding assembly such as brake calipers. Actuation of the brake lever by a rider's hand causes an axial displacement of a linking cable, in turn causing brake shoes attached to the brake calipers to clamp down on the rim of a bicycle wheel, thereby slowing the bicycle. Likewise, bicycle gear shifting systems comprise an actuating assembly or shifter, operatively connected by a Bowden cable to a responding assembly, typically a derailleur. Actuation of the shifter by a rider's hand causes an axial displacement of a linking cable, which in turn causes the derailleur to urge a drive chain between various sprockets of a freewheel at the real derailleur or chainrings at the front derailleur, thereby effecting a gear shift. Although herein described with respect to brake lever assemblies, the present invention is an improvement to all cable actuating assemblies.
Typically, in brake lever assemblies, the brake lever is pivotally attached to a brake housing which is in turn clamped to the handlebar near a rider's handgrip. The control cable is routed through the brake housing, with a cable end removably attached to the brake lever. Likewise, in shifter actuating assemblies, the cable is routed through the actuator housing, with a cable end removably attached to the shift actuating member, be it a rotatable or lever-type actuating, device. Removably attaching the cable end to the brake lever permits a rider to replace a broken cable quickly without having to disassemble the brake lever or feed the entire length of cable through the housing. This is especially critical when replacing cables under field conditions. In order to accommodate cable replacement, existing brake lever assemblies typically have a slot cut along the length of the front of the brake housing, through which the cable is inserted into the housing FIG. 1 is an isometric vies of the components comprising a conventional brake lever assembled including a full length slot 19 cut along the length of the top of brake housing 11. Such a slot significantly reduces the flexural and torsional stiffness of the brake housing, allowing the brake housing to be spread open during frontal impact loading of the housing itself or due to transverse loading on the brake lever. Because the brake lever assembly is positioned ahead of the handlebar, it is particularly susceptible to such impact loading. This is especially true in off-road mountain biking, where there is a greater threat of collision with natural obstacles. Because the brake housing functions as the pivot anchor for the brake lever, it is essential that it resist deformation and retain its shape, thereby preventing brake lever rotation around an axis other than that of the pivot pin and ensuring smooth lever operation
Other existing brake lever assemblies have a partial slot and adjoining insertion hole cut across the top or sides of the brake housing, the insertion hole sufficiently sized to receive a cable end. FIGS. 2 and 3 are perspective and side views of conventional brake lever assemblies showing partial slots 62, 63 and insertion holes 64, 65 along the top and sides of brake housing 11 respectively. Although stiffer than fully-slotted brake housings, these brake housings, nevertheless, are weakened by a relatively thin strip of material b, located between the end of the insertion hole and the housing edge, that likewise produces a relatively flexible brake housing. With the increased reliance on lighter weight plastic versus metallic bicycle components, it becomes increasingly important to design more rigid and structurally efficient brake lever components.